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Interesting and/or useful TI programs


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TI99Dir by: Mr. F.B. Kaal

 

Is one of the most useful programs in existence in support of the TI (IMHO), even though it's a PC program!

His new version "55a" (see attachment), also has a new selection when making disk images.

It will now create DSSD 80 track images for those who've modified their TI floppy disk controllers!

 

Whether you use a Nano-PEB, use an emulator or use an HxC or an HDX, there is always a need for Ti99Dir!

ti99dir55a.zip

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TI99Dir by: Mr. F.B. Kaal

 

Is one of the most useful programs in existence in support of the TI (IMHO), even though it's a PC program!

His new version "55a" (see attachment), also has a new selection when making disk images.

It will now create DSSD 80 track images for those who've modified their TI floppy disk controllers!

 

Whether you use a Nano-PEB, use an emulator or use an HxC or an HDX, there is always a need for Ti99Dir!

 

Thanks. I have been running 5.3b. I did not realize I had 5.5 downloaded and never un-zipped!

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How come Ti99Dir does not support DSQD or SSQD?

 

It does support the DSQD capacity. IMHO there would be little reason to emulate SSQD as 80-track hardware would presume double sided capability, though his program may do so. Also be wary of the higher capacities and TI99Dir. Unless Fred has fixed the bugs, there are still some file handling issues with disk images using more than one sector per allocation unit, i.e. disks over 1600 sectors. The issues manifest themselves most often when manipulating fixed and variable record files on the images.

 

A few comments about density that come to mind:

  • Single density: a diskette formatted to 9 sectors per track.
  • Double density: a diskette formatted to 18- or 16- sectors per track. Usually a 40 track diskette.
  • Quad density : a diskette formatted to 18-sectors per track AND 80 tracks. The tracks are doubled from 40 to 80, hence "quad" density. NOT equivalent to High Density. There may be 16-sector/track quad density disks created by the older Myarc cards from the early days.
  • High density: a diskette formatted to 36 sectors per track and 80 tracks. Only the Myarc HFDC may utilize this format.
  • Single density diskettes were/are often single sided for compatibility with the old, single-sided drives that came with the PEB.
  • The remaining formats are often presumed double-sided as people updated their drives and controller cards to make use of the extra capacity.
  • The early Myarc FDC DSR formatted double density at 16-sectors/track and was later updated to 18-sectors/track. The MPES is hard-coded to 16-sectors/track. If I recall correctly, only the Myarc FDC and Myarc HFDC can properly handle the early 16-sector/track format, so its generally best to avoid it.
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Actually, the 16-sector Myarc format follows the TI DSDD specification, used in both the Hex-Bus Floppy and the TI DSDD card for the PEB. CorComp didn't follow the TI design docs--and initially sold a lot more cards, so their format became the de facto standard.

Do not quite follow the logic of going from 9 Sectors per track to 16 instead of 18?

I mean 2 times 9 is 18 not 16 and how could you call it Double or Quad when you do the math and it is so far off?

 

I think the reason for using 18 sectors per track was based on simple math not making any sense.

36 Sectors per track makes more sense then 32 as 9 will not go into 32 will it?

Nor will 9 go into 16, so not really double and not really quad either, accurately you would need a more descriptive name as DD and QD do not fit.

Edited by RXB
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Oddly enough, quite a few early computer systems used the 320K double density mode--even the IBM PC used it as a valid format for a while. It survived as a valid format through most of the revisions of MS-DOS, even though it was almost never used after DOS 2 or so.

 

It all had to do with the hardware--the drives could work up to 360K, but the reliability of the disk positioning mechanisms was such that an overcautious engineer factored that in by using it at less than capacity to ensure super-reliable functionality. The thing was, by the time everyone was actually using double density, the reliability of the drive mechanisms had increased to the point where the overcautious limitation was no longer relevant.

 

Double density has to do with using the sector between the sectors (the one that was only used for timing in single density mode) for data--the number of sectors is actually irrelevant.

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